Dinarmus

Thomson, 1878

Dinarmus is a of in the with nearly distribution. in this genus are larval-pupal of (: Bruchinae), particularly pests of stored legume seeds such as cowpea. The genus includes economically important agents, notably D. basalis and D. vagabundus, which are deployed in programs targeting Callosobruchus species. Research on D. basalis has revealed complex discrimination behaviors, facultative , and olfactory host location mechanisms.

Pronunciation

How to pronounce Dinarmus: /dɪˈnɑːrməs/

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Habitat

Primarily associated with stored legume products and agricultural settings where occur. have been documented in cowpea systems, vetch fields, and other environments where pulse beetle develop on Fabaceae seeds.

Distribution

Almost . Documented occurrences include: semiarid regions of Rio Grande do Norte state (Brazil) on cowpea; widespread distribution in association with stored product pests globally.

Host Associations

Callosobruchus maculatus - Primary for D. basalis; pest of cowpea (Vigna unguiculata)
Callosobruchus chinensis - for D. basalis; pulse pest
Bruchus brachialis - for D. acutus; vetch
Bruchidius atrolineatus - for D. basalis in laboratory studies
Zabrotes subfasciatus - Documented for D. basalis on genetically modified cowpea

Life Cycle

Larval-pupal development. Females externally on . Solitary development: typically one emerges per host, though occurs. Developmental plasticity observed in response to host quality and parasitoid .

Behavior

discrimination: females distinguish unparasitized hosts from those parasitized 8-72 hours previously by themselves or , using host-quality markers including substances emitted during and larval-associated cues. Olfactory host location using chemical cues from hosts and host plants. Post- early learning involved in host recognition. occurs despite discrimination ability, with gains possible when second survival probability is favorable. Virgin females exhibit different host selection strategies than inseminated females, choosing smaller, easier hosts to maximize lifetime egg production. Facultative hyperparasitism documented as extreme survival .

Ecological Role

agent of in stored legume products. Regulates of major agricultural pests including Callosobruchus that destroy cowpea and other pulse . with legume plants and bruchid pests demonstrate cascading effects of macronutrient content on and sex ratios.

Human Relevance

Used in to prevent destruction of cowpea by Callosobruchus . feeding supplementation (particularly ) enhances progeny production and . Impact assessed in contexts of genetically modified crops and applications.

More Details

Sex allocation and host choice

Inseminated females of D. basalis manipulate offspring sex ratios and preferentially select larger, higher-quality (17-day-old vs. 12-13-day-old hosts), while virgin females produce only male offspring and select smaller hosts to maximize lifetime through energy .

Nutritional ecology

Larval sugar content in C. maculatus positively correlates with D. basalis sex ratio and parameters, demonstrating bottom-up effects through the -pest- .

Superparasitism mechanisms

discrimination in D. basalis involves individual-specific markers; rates often exceed self-superparasitism rates. One substance is female-emitted during ; another is released by 16-24 hour-old .